Toothbrush drive unit



FIG. 1 is a perspective view of a toothbrush drive unit embodying the new design;

FIG. 2 is a right side view, the left side being a mirror image thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The broken lines in the drawings depict portions of the toothbrush drive unit that form no part of the claimed design. 

CLAIM The ornamental design for a toothbrush drive unit, as shown and described. 